Method for silicon substrate APD (Avalanche Photodiode) infrared sensitivity enhancement

Abstract

The invention relates to a method for silicon substrate APD (Avalanche Photodiode) infrared sensitivity enhancement, which belongs to the manufacturing field of photoelectric detectors. According to the method, a femtosecond irradiation doping process is carried out on a substrate of a silicon substrate APD under an SF6 gas atmosphere. According to the method, femtosecond laser is utilized to irradiate a silicon wafer under the SF6 gas atmosphere, so that the infrared sensitivity in a near-infrared area is obviously enhanced, the quantum detection efficiency at a 1064nm wave band is improved to 30 percent from original 13 percent, the cut-off wavelength of silicon substrate APD absorption-photons is extended, and the application of a silicon substrate APD device in near-infrared small-signal detection, the photo-communication field and the laser industry can be further expanded.

Description

technical field [0001] The invention belongs to the field of photodetection device manufacture and relates to a method for enhancing infrared sensitivity of a silicon-based APD. Background technique [0002] Silicon is widely used in the semiconductor field to manufacture semiconductor devices, but since the band gap of silicon is 1.12eV, the absorption of infrared light by silicon is greatly limited. Due to the development of the communication industry and the wide application of 1064nm lasers, it is urgent to expand the response width of APD. More advanced avalanche photodiodes (APDs) have been designed and constructed. However, domestic silicon-based APDs with high quantum response at 1064nm and silicon-based APD arrays with high quality and low price and large sensing area still do not meet the market demand. There are two reasons that restrict the application of silicon-based APDs in this direction. First, the band gap of silicon at 300K is 1.12eV, which leads to the ...

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Problems solved by technology

However, domestic silicon-based APDs with higher quantum response at 1064nm and high-quality and cheap silicon-based APD arrays with larger sensing areas still do not meet market demand.

There are two reasons that restrict the application of silicon-based APDs in this direction. First, the band gap of silicon at 300K is 1.12eV, which leads to the cut-off of silicon’s absorption of light at 1100nm; second, silicon is an indirect band gap material, which leads to the actual The absorption efficiency of medium-silicon-based APD devices is very low near the cut-off wavelength

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